SALT LAKE CITY — Mitt Romney is preparing to announce a bid for Utah's Senate seat held by retiring Orrin Hatch, a position some hope the 2012 GOP presidential nominee will use to continue his biting criticism of President Donald Trump.

Romney, who once called Trump "a phony" who was unfit for office, is not expected to address the president in an announcement video he has prepared for release online, according to people with direct knowledge of his plans.

Romney had planned to release the video on Thursday, they said, but he tweeted Wednesday night that he would not make an announcement about Utah's Senate race because of the deadly school shooting in Florida. It wasn't clear when he would reschedule his announcement.

Expected to be a heavy favorite to win Hatch's seat, Romney is planning a campaign with a laser-focus on Utah and will suggest that Washington has much to learn from the state the former Massachusetts governor now calls home, said those with knowledge of his plans.

"I think Mitt's going to make it very clear that he's not running for the Senate because of or in spite of anything to do with Donald Trump," said Spencer Zwick, Romney's former fundraising chief who now leads fundraising efforts for House Speaker Paul Ryan. "I think Mitt Romney would be running for the Senate whether Donald Trump was the president or Hillary Clinton was the president."

Out of respect for the victims and their families, I will not be making an announcement tomorrow about the Senate race. (2/2)

Romney's small team of longtime advisers plans to maintain a low profile. Having turned down repeated requests for national media appearances in recent days, Romney is carefully designing his campaign launch to avoid media questions about Trump.

Those with knowledge of his plans spoke on the condition of anonymity because they weren't authorized to speak publicly.

Romney, one of the most famous Mormons, is widely liked and respected in Utah, which is heavily Mormon. He attended Brigham Young University in Provo, helped turn around the scandal-plagued 2002 Winter Olympics in Salt Lake City and made Utah his primary home after losing the 2012 presidential election.

In addition to his name recognition, Romney has a deep network of fundraisers and his own personal wealth to help carry him. Those close to him suggest he will not seek financial aid from any super PACs or Washington-based campaign committees.

If he becomes Utah's next senator, some supporters hope that the one-time Trump critic could serve as a political and moral counterweight to a president they see as divisive, erratic and undignified.

Kirk Jowers, the former chairman and general counsel of Romney's leadership PACs, said Romney "will always be a straight shooter" and will speak up and the support the president when he takes actions that are good for America.

"If President Trump says or does something that he finds offensive or divisive, unnecessarily divisive, then I think you will continue to hear Romney as the voice of reason and conscience in the Republican Party," Jowers said.

Though he delivered a scathing speech denouncing Trump during the 2016 presidential election, Romney softened his stance after Trump won the presidency and put himself forward as a candidate for secretary of state. But he resumed his criticism last year, calling out the president for blaming "both sides" following a deadly white supremacist rally in Charlottesville, Virginia.

Trump, in turn, has criticized Romney for his failed presidential bids in 2008 and 2012, saying he "choked like a dog."

Any efforts by Trump to block Romney are unlikely to resonate in Utah, where the president received a lukewarm reception from Mormons who were repelled by his brash demeanor and degrading comments about women and minorities.

Former Rep. Jason Chaffetz, a Utah Republican who resigned last summer and became a Fox News commentator, said Romney's clashes with Trump won't hurt him with Utah voters but that he does need to explain why he wants to be their senator.

"I do think people want to know he's running not just to be an agitator to the president. I don't think that's going to win the hearts and minds, but I also don't think he's going to do that," Chaffetz said. "Mitt Romney's always been diplomatic. It's why Donald Trump almost named him the secretary of state. He's very deliberate and smart in what he does."

Romney isn't expected to face any serious challenges for the seat. Even Utah's conservatives, who see him as too moderate and establishment for their liking, admit they respect him and are unlikely to block him.

However, some in the state see Romney as an outsider who is simply banking on his fame.

Utah Republican Party Chairman Rob Anderson told The Salt Lake Tribune that Romney is "keeping out candidates that I think would be a better fit for Utah because, let's face it, Mitt Romney doesn't live here, his kids weren't born here, he doesn't shop here."

Anderson told The Associated Press that he was just repeating concerns and complaints he'd heard from others, but said he's excited to see the interest that Romney is generating. He said he spoke with Romney after the Tribune article was published, and Romney told him he would travel all corners of Utah to hear people's concerns.

Hatch, one of the longest-serving senators in U.S. history after more than four decades in office, began floating Romney's name last year as his potential successor.

When Hatch won re-election in 2012, he pledged that his seventh term would be his last. He flirted with breaking that promise and suggested he might run again in 2018 with the encouragement of Trump, who sought to block Romney.

In the end, Hatch decided to stick with his promise, saying, "Every good fighter knows when to hang up the gloves."